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GENERAL DESCRIPTION
The PT4211 is a continuous conduction mode inductive
step
-
down converter, designed for driving single or
multiple series connected LEDs from a voltage source
higher than the LED voltage. The device operates from
an input supply between
5
V and 30V and provides an
externally adjustable output current of up to
35
0mA.
The PT4
2
11 includes the output switch and a high
-
side
output current sensing circuit, which uses
an external
resistor to set the nominal average output current, and a
dedicate
d DIM input accepts a wide range of pulsed
dimming. Applying a voltage of
0.
4
V
or lower to the
DIM pin turns the output off and switches the device
into a low current standby state.
Built
-
in Soft Over
Temperature Protection
pro
tects the device from over
te
mperature damage.
The PT4
2
11 is available in SOT23
-
5 package
.
F
EATURES
Simple low parts count
Wide input voltage range:
5
V to
3
0V
Up to 35 0m A output current
PWM dimming
3% output current accuracy
.
Up to 1MHz switching frequency
Typical
3
% output current a
ccuracy
Inherent open - circuit LED protection
High efficiency (up to 9
3
%)
Adjustable Constant LED Current
High - Side Current Sense
Hysteretic Control: No Compensation
Soft Over Temperature Protection
APPLICATION
Low voltage halogen replacement LEDs
Automotiv e lighting
LED back
-
up lighting
Illuminated signs
|
